diff mbox

[v12,05/16] block: Set "share-rw" flag in drive-backup when sync=none

Message ID 20170123123056.30383-6-famz@redhat.com
State New
Headers show

Commit Message

Fam Zheng Jan. 23, 2017, 12:30 p.m. UTC 
In this case we may open the source's backing image chain multiple
times. Setting share flag means the new open won't try to acquire or
check any lock, once we implement image locking.

Signed-off-by: Fam Zheng <famz@redhat.com>
---
 blockdev.c | 3 +++
 1 file changed, 3 insertions(+)

Comments

Max Reitz Feb. 5, 2017, 9:57 p.m. UTC | #1 
On 23.01.2017 13:30, Fam Zheng wrote:
> In this case we may open the source's backing image chain multiple
> times. Setting share flag means the new open won't try to acquire or
> check any lock, once we implement image locking.
> 
> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---
>  blockdev.c | 3 +++
>  1 file changed, 3 insertions(+)

Reviewed-by: Max Reitz <mreitz@redhat.com>
diff mbox

Patch

diff --git a/blockdev.c b/blockdev.c
index 245e1e1..c97e97f 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -3177,6 +3177,9 @@  static BlockJob *do_drive_backup(DriveBackup *backup, BlockJobTxn *txn,
     }
     if (backup->sync == MIRROR_SYNC_MODE_NONE) {
         source = bs;
+        /* FIXME: block layer should really open target with BDRV_O_NO_BACKING
+         * and reuse source's backing chain, if they share one. */
+        flags |= BDRV_O_SHARE_RW;
     }
 
     size = bdrv_getlength(bs);